RSS feeds still make me crazy when they don’t work on some of my sites.
I also followed the instructions and a few examples when I tried yahoo pipes to create an automatic retweet feed. The prewrriten ones worked only some of the time. The instructions make it look sooo easy.
Anyway, I just tried the rssmix.com site.
I added the rss feeds from two of my blogs.
The result was presented in an html format Mix ID 3072360
and an RSS format RSSMix.com Mix ID 3072360
If you do the same for whatever you want to combine, you could bookmark the links in your browser.
I don’t want to showcase my ignorance here, but isn’t combining rss feeds the purpose those ‘rss aggregators’ like ‘my yahoo’ (which I never use) and google (they always seem to show up nice in firefox and as boring code in chrome).